去垂体裸大鼠（IPL裸大鼠）中解离的雌二醇（E2）对垂体-睾丸轴的作用

Dissociated estradiol (E2) action on the pituitary-testicular axis in a genetically hypoprolactinemic rat (IPL nude rat).

作者信息

Cohen H, Guillaumot P, Sabbagh I

机构信息

INSERM U 34, Hôpital Debrousse, Lyon, France.

出版信息

J Steroid Biochem. 1988;30(1-6):407-10. doi: 10.1016/0022-4731(88)90132-x.

DOI:10.1016/0022-4731(88)90132-x

PMID:3386268

Abstract

Prolactin (PRL) has been reported to be a possible mediator in the estradiol (E2)-induced inhibition of the pituitary-testicular axis. In order to better characterize the role of PRL, we studied the action of chronic hypoprolactinemia on this E2 inhibitory effect, using a genetically hypoprolactinemic rat (IPL nude). Normal and IPL nude adult male rats were injected either with vehicle or with E2 valerianate (4 mg/rat) once a week for 2 weeks. Rats were decapitated 7 days after the last injection. Results showed that E2 increased, similarly in both strains, pituitary weight and serum PRL levels. Serum testosterone values were reduced by 96% in both strains. However, testis weight was significantly reduced by 30% in normal rat, while in IPL nude rat, no significant decrease was observed. PRL binding sites, expressed as fmol/mg protein, were reduced in normal rat by 40%. No decrease was found in IPL nude rat. The dissociated E2 action observed in IPL nude rat suggested that only testicular growth inhibition could be mediated by PRL and confirm that testosterone level decrease could be due to a direct action of E2 on Leydig cells.

摘要

据报道，催乳素（PRL）可能是雌二醇（E2）诱导的垂体-睾丸轴抑制作用的介质。为了更好地描述PRL的作用，我们使用遗传性低催乳素血症大鼠（IPL裸鼠）研究了慢性低催乳素血症对这种E2抑制作用的影响。正常成年雄性大鼠和IPL裸鼠每周注射一次溶剂或戊酸雌二醇（4mg/只），共2周。最后一次注射7天后断头处死大鼠。结果显示，两种品系中E2均使垂体重量和血清PRL水平升高。两种品系的血清睾酮值均降低了96%。然而，正常大鼠的睾丸重量显著降低了30%，而IPL裸鼠未观察到显著下降。以fmol/mg蛋白表示的PRL结合位点在正常大鼠中降低了40%。在IPL裸鼠中未发现降低。在IPL裸鼠中观察到的E2作用解离表明，只有睾丸生长抑制可能由PRL介导，并证实睾酮水平降低可能是由于E2对睾丸间质细胞的直接作用。